Anyone can make mistakes when entering an email into an input field. Therefore, it is the developer's responsibility to check if the user has entered a valid email string. There are many libraries available for validating email addresses, which we can use with various JavaScript frameworks, but not with plain JavaScript. However, if we want to use any library, we need to use its CDN.
Here we will validate email addresses in plain JavaScript using regular expressions.
Regular expression used in Example 1
We used the following regular expression pattern in Example 1 to validate the email.
let regex = /^[a-z0-9]+@[a-z]+\.[a-z]{2,3}$/;
Users can follow the explanation of the above regular expressions below.
^ - It is the beginning of the string.
[a-z0-9] - Any character between a through z and 0 through 9 at the beginning of the string.
@ - The string should contain the "@" character after some alphanumeric characters.
[a-z] - There is at least one character between a and z after the "@" character in the string.
\. – The email should contain a dot, followed by some characters, followed by the “@” character
[a-z]{2,3}$ - It should contain two or three alphabetic characters at the end of the string. ‘$’ represents the end of the string.
Example 1
In the example below, when the user clicks the button, it calls the validateEmail() function. In the validateEmail() function, we use JavaScript’s Prompt () method to get the user’s email input.
After that, we created the regular expression as explained in the above syntax. We use regular expressions to test the user's email input via the test() method, which returns a boolean value based on whether the email matches the regular expression.
<html>
<body>
<h3 id="Using-the-i-Regular-expression-i-to-validate-email-in-JavaScript">Using the <i> Regular expression </i> to validate email in JavaScript </h3>
<div id = "output"> </div>
<button onclick = "validateEmail()"> Validate any email </button>
<script>
var output = document.getElementById('output');
function validateEmail() {
let userEmail = prompt("Enter your email.", "you@gmail.com");
let regex = /^[a-z0-9]+@[a-z]+\.[a-z]{2,3}$/;
let result = regex.test(userEmail);
if (result) {
output.innerHTML = "The " + userEmail + " is a valid email address!";
} else {
output.innerHTML = "The " + userEmail + " is not a valid email address!";
}
}
</script>
</body>
</html>
Regular expression used in Example 2
We used the following regular expression pattern in Example 2 to validate the email.
let regex = new RegExp(/\S+@\S+\.\S+/);
Users can follow the explanation of the above regular expressions below.
\S - It stands for any alphanumeric word.
\. – represents the dot character.
Basically, the above pattern matches email addresses of type word@word.word.
Example 2
In the example below, we create the email input using HTML. User can enter any email in the input field. After entering the email in the input, the user needs to click on the "Validate email entered" button, which will call the submitEmail() function.
In the submitEmail() function, we use the above regular expression and test() method to check the email string entered by the user.
In the output, the user can enter various emails and observe the output.
<html>
<head>
<style>
div {
font-size: 1rem;
color: red;
margin: 0.1rem 1rem;
}
</style>
</head>
<body>
<h2 id="Using-the-i-Regular-expression-i-to-validate-email-in-JavaScript">Using the <i> Regular expression </i> to validate email in JavaScript </h2>
<div id = "output"> </div>
<input type = "email" id = "emailInput" placeholder = "abc@gmail.com">
<br><br>
<button onclick = "submitEmail()"> Validate input email </button>
<script>
var output = document.getElementById('output');
function submitEmail() {
let userEmail = document.getElementById('emailInput').value;
let regex = new RegExp(/\S+@\S+\.\S+/);
let isValid = regex.test(userEmail);
if (isValid) {
output.innerHTML = "The " + userEmail + " is a valid email address!";
} else {
output.innerHTML = "The " + userEmail + " is not a valid email address!";
}
}
</script>
</body>
</html>
We learned to use regular expressions to validate email strings. We have seen two regular expressions and explained them so that beginners can understand how to create regular expressions for emails.
Additionally, developers can create custom regular expressions to validate email addresses based on their needs.
The above is the detailed content of How to validate email address using RegExp in JavaScript?. For more information, please follow other related articles on the PHP Chinese website!
Python vs. JavaScript: A Comparative Analysis for DevelopersMay 09, 2025 am 12:22 AMThe main difference between Python and JavaScript is the type system and application scenarios. 1. Python uses dynamic types, suitable for scientific computing and data analysis. 2. JavaScript adopts weak types and is widely used in front-end and full-stack development. The two have their own advantages in asynchronous programming and performance optimization, and should be decided according to project requirements when choosing.
Python vs. JavaScript: Choosing the Right Tool for the JobMay 08, 2025 am 12:10 AMWhether to choose Python or JavaScript depends on the project type: 1) Choose Python for data science and automation tasks; 2) Choose JavaScript for front-end and full-stack development. Python is favored for its powerful library in data processing and automation, while JavaScript is indispensable for its advantages in web interaction and full-stack development.
Python and JavaScript: Understanding the Strengths of EachMay 06, 2025 am 12:15 AMPython and JavaScript each have their own advantages, and the choice depends on project needs and personal preferences. 1. Python is easy to learn, with concise syntax, suitable for data science and back-end development, but has a slow execution speed. 2. JavaScript is everywhere in front-end development and has strong asynchronous programming capabilities. Node.js makes it suitable for full-stack development, but the syntax may be complex and error-prone.
JavaScript's Core: Is It Built on C or C ?May 05, 2025 am 12:07 AMJavaScriptisnotbuiltonCorC ;it'saninterpretedlanguagethatrunsonenginesoftenwritteninC .1)JavaScriptwasdesignedasalightweight,interpretedlanguageforwebbrowsers.2)EnginesevolvedfromsimpleinterpreterstoJITcompilers,typicallyinC ,improvingperformance.
JavaScript Applications: From Front-End to Back-EndMay 04, 2025 am 12:12 AMJavaScript can be used for front-end and back-end development. The front-end enhances the user experience through DOM operations, and the back-end handles server tasks through Node.js. 1. Front-end example: Change the content of the web page text. 2. Backend example: Create a Node.js server.
Python vs. JavaScript: Which Language Should You Learn?May 03, 2025 am 12:10 AMChoosing Python or JavaScript should be based on career development, learning curve and ecosystem: 1) Career development: Python is suitable for data science and back-end development, while JavaScript is suitable for front-end and full-stack development. 2) Learning curve: Python syntax is concise and suitable for beginners; JavaScript syntax is flexible. 3) Ecosystem: Python has rich scientific computing libraries, and JavaScript has a powerful front-end framework.
JavaScript Frameworks: Powering Modern Web DevelopmentMay 02, 2025 am 12:04 AMThe power of the JavaScript framework lies in simplifying development, improving user experience and application performance. When choosing a framework, consider: 1. Project size and complexity, 2. Team experience, 3. Ecosystem and community support.
The Relationship Between JavaScript, C , and BrowsersMay 01, 2025 am 12:06 AMIntroduction I know you may find it strange, what exactly does JavaScript, C and browser have to do? They seem to be unrelated, but in fact, they play a very important role in modern web development. Today we will discuss the close connection between these three. Through this article, you will learn how JavaScript runs in the browser, the role of C in the browser engine, and how they work together to drive rendering and interaction of web pages. We all know the relationship between JavaScript and browser. JavaScript is the core language of front-end development. It runs directly in the browser, making web pages vivid and interesting. Have you ever wondered why JavaScr
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
SecLists
SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.
SublimeText3 English version
Recommended: Win version, supports code prompts!
Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.
Dreamweaver CS6
Visual web development tools
Atom editor mac version download
The most popular open source editor
